| 摘要: |
| 过2018年5月17日和2019年4月27日2次冰雹天气过程，结合冰雹云单体回波演变特征，着重分析了冰雹云单体Zh、Zdr、φdp、ρhv等偏振参量特征，以及不同相态降水粒子分布与温度形成环境条件的对应关系。分析结果表明：（1）若以45 dBz回波高度在0℃层高度以上、回波强度Z≥55 dBz、VIL≥20 g•km-2作为冰雹识别指标，比降雹时间提前1-3体扫观测时间，冰雹预警时间提前量为6~18min。（2）非球形大粒子区的Zdr在2.8~5.4 dB之间，φdp在179~191°之间，ρhv在0.85~0.99之间，与强回波区相对应，主要是有大雨滴粒子群所组成，近似于球形大粒子区的Zdr在-2.3~1.2 dB之间，φdp在180~235°之间，ρhv在0.54~0.90之间，主要分布的是霰或冰雹等球形粒子。（3）当近似于球形粒子（冰雹）位于非球形粒子（雨滴）的前侧且存在Zdr正中心区和负中心区时，这是由于风向风速的拖曳作用，使大雨滴团移动较小，霰或小冰雹朝向风的方向移动较快而使其处于强回波区前沿的结果。（4）本研究中粒子识别分类算法没有考虑水凝物粒子所存在的温度环境条件，导致暖云中存在湿雪（WS）、冰晶（CR）等固态降水粒子，且缺少霰粒子分类识别产品，因而需要对水凝物粒子分类识别算法予以改进。 |
| 关键词: 冰雹云;演变特征;偏振参量;粒子识别;预警时间 |
| DOI： |
| 投稿时间：2024-05-08修订日期：2024-05-08 |
| 基金项目: |
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| Radar Observation Study on the Evolution Characteristics of Hail_Cloud in Weining, Guizhou |
| Zou Shuping,KE Liping,ZENG Yong,LUO Xiong,HUANG Yu,LI Lili |
| (Guizhou Mountainous Meteorological Science research Institute;Bijie Meteorological Bureaue;Guizhou Meteorological Observatory) |
| Abstract: |
| Through the Two hailstorms processes on May 17, 2018 and April 27, 2019, combined with the radar echo evolution characteristics of the individual hail_cloud cells, the characteristics of the polarization parameters such as Zh,Zdr,φdp, and ρhv of the individual hail_cloud cells were analyzed, and The corresponding relationship between the distribution of precipitation particles in different phases and temperature forms environmental conditions.The analysis results show that: (1) If the 45 dBz echo height is above the 0℃ layer height, the echo intensity Z≥55 dBz, and VIL≥20g.km-2 are used as hail identification indicators, the body scanning observation time will be 1-3 times earlier than the hailfall time. , the hail warning time advance is 6-18 minutes.(2) The Zdr of the non-spherical large particle area is between 2.8-5.4 dB, φdp is between 179-191°, and ρhvis between 0.85-0.99, which corresponds to the strong echo area and mainly contains large raindrop particles. Composed of groups, the ρhvof the approximately spherical large particle area is between -2.3-1.2dB, φdp is between 180-235°, and ρhv is between 0.54-0.90. The main distribution is spherical particles such as graupel or hail.(3) When approximately spherical particles (hail) are located on the front side of non-spherical particles (raindrops) and there are positive and negative central areas of Zdr , this is due to the drag effect of wind direction and speed, which makes the large raindrop cluster move smaller. The result of graupel or small hail moving faster in the direction of the wind, placing it at the front of the strong echo zone.(4)Since the particle identification and classification algorithm in this study did not consider the temperature and environmental conditions in which hydrometeor particles exist, solid precipitation particles such as wet snow (WS) and ice crystals (CR) exist in warm clouds, and there is a lack of graupel particle classification and identification products. Therefore, The hydrometeor particle classification and identification algorithm needs to be improved. |
| Key words: hail_cloud; evolution characteristics; polarization parameters; particle identification; warning time |
